Williams have named 20-year-old Finn Valtteri Bottas as official test driver for the year.

Bottas replaces Nico Hulkenberg who has made the step up to team driver for 2010, with the young German to partner veteran Rubens Barrichello.

After starting out on the traditional route of karts, Bottas then won the Eurocup and NEC Championships in Formula Renault in 2008.

Graduating to Formula 3 last year, Bottas was the highest-placed rookie, finishing third in the championship, while he also won the F3 Masters.

"Valtterri's CV is very impressive, with a long list of success in the right junior formulae," said team principal Frank Williams.

"We hope the role of official test driver in our squad will provide him with another step in his development."

Commenting on his appointment, Bottas said: "This is an important step in my career, but now the real work starts to get to the top.

"This opportunity gives me even more positive energy to improve as a driver and achieve my future targets as my ultimate goal will be to become Formula One world champion one day."